Electrochromic window fabrication methods

ABSTRACT

Methods of manufacturing electrochromic windows are described. Insulated glass units (IGU&#39;s) are protected, e.g. during handling and shipping, by a protective bumper. The bumper can be custom made using IGU dimension data received from the IGU fabrication tool. The bumper may be made of environmentally friendly materials. Laser isolation configurations and related methods of patterning and/or configuring an electrochromic device on a substrate are described. Edge deletion is used to ensure a good seal between spacer and glass in an IGU and thus better protection of an electrochromic device sealed in the IGU. Configurations for protecting the electrochromic device edge in the primary seal and maximizing viewable area in an electrochromic pane of an IGU are also described.

CROSS-REFERENCES TO RELATED APPLICATIONS

This is a divisional of U.S. patent application Ser. No. 15/364,162,filed on Nov. 29, 2016 and titled “ELECTROCHROMIC WINDOW FABRICATIONMETHODS,” which is a divisional of U.S. patent application Ser. No.14/512,297 (issued as U.S. Pat. No. 9,703,167), filed on Oct. 10, 2014and titled “ELECTROCHROMIC WINDOW FABRICATION METHODS,” which is adivisional of U.S. patent application Ser. No. 13/456,056, filed on Apr.25, 2012 and titled “ELECTROCHROMIC WINDOW FABRICATION METHODS;” U.S.patent application Ser. No. 13/456,056 is a continuation-in-part of U.S.patent application Ser. No. 13/431,729 (issued as U.S. Pat. No.9,102,124), filed on Mar. 27, 2012 and titled “ELECTROCHROMIC WINDOWFABRICATION METHODS;” U.S. patent application Ser. No. 13/456,056 isalso a continuation-in-part of U.S. patent application Ser. No.13/312,057 (issued as U.S. Pat. No. 8,711,465), filed on Dec. 6, 2011and titled “SPACERS FOR INSULATED GLASS UNITS;” U.S. patent applicationSer. No. 13/431,729 is a continuation of U.S. patent application Ser.No. 12/941,882 (issued as U.S. Pat. No. 8,164,818), filed on Nov. 8,2010 and titled “ELECTROCHROMIC WINDOW FABRICATION METHODS;” U.S. patentapplication Ser. No. 13/312,057 claims priority to U.S. ProvisionalPatent Application No. 61/421,154, filed on Dec. 8, 2010 and titled“IMPROVED SEPARATORS FOR INSULATED GLASS UNITS,” and U.S. ProvisionalPatent Application No. 61/435,914, filed on Jan. 25, 2011 and titled“SEPARATORS FOR INSULATED GLASS UNITS;” each of these applications ishereby incorporated by reference in its entirety and for all purposes.

FIELD

The invention relates generally to electrochromic devices, moreparticularly to electrochromic windows.

BACKGROUND

Electrochromism is a phenomenon in which a material exhibits areversible electrochemically-mediated change in an optical property whenplaced in a different electronic state, typically by being subjected toa voltage change. The optical property is typically one or more ofcolor, transmittance, absorbance, and reflectance. One well knownelectrochromic material is tungsten oxide (WO₃). Tungsten oxide is acathodic electrochromic material in which a coloration transition,transparent to blue, occurs by electrochemical reduction.

Electrochromic materials may be incorporated into, for example, windowsfor home, commercial and other uses. The color, transmittance,absorbance, and/or reflectance of such windows may be changed byinducing a change in the electrochromic material, that is,electrochromic windows are windows that can be darkened or lightenedelectronically. A small voltage applied to an electrochromic device ofthe window will cause them to darken; reversing the voltage causes themto lighten. This capability allows control of the amount of light thatpasses through the windows, and presents an opportunity forelectrochromic windows to be used as energy-saving devices.

While electrochromism was discovered in the 1960's, electrochromicdevices, and particularly electrochromic windows, still unfortunatelysuffer various problems and have not begun to realize their fullcommercial potential despite many recent advancements in electrochromictechnology, apparatus and related methods of making and/or usingelectrochromic devices.

SUMMARY

Methods of manufacturing electrochromic windows are described. Anelectrochromic (or “EC”) device is fabricated to substantially cover aglass sheet, for example float glass, and a cutting pattern is definedbased on one or more areas in the device from which one or moreelectrochromic panes are cut. In various embodiments, the cuttingpattern is defined, at least in part, only after the electrochromicdevice has been fabricated and characterized. In some cases, the cuttingpattern is defined after taking into account the overall quality of theelectrochromic device and/or the location of defects in the device. Forexample, the electrochromic device may be probed to determine thelocation of all defects or certain types or classes of defects. Thecutting pattern then excludes those defects from usable window panes,resulting in an overall high-quality product and a high-yield process.In another example, the complete device sheet is inspected to determinethe leakage current of the EC device or the resistivity of one or bothof the EC device's electrode layers. If the leakage current is higherthan a threshold or the resistivity of a TCO layer is higher than athreshold, the size of the electrochromic panes is limited to ensurethat the resulting windows perform adequately in spite of the device'shigh leakage or the TCO's high resistivity.

In certain embodiments, inspection of the glass sheet and/or individualpanes is performed at one or more points in the fabrication process.Various optical, electrical, chemical and/or mechanical metrology testsmay be used to probe the product, for example, after EC device formationin order to define a cutting pattern for the glass sheet and/or afterthe individual panes are cut to test the individual panes. Individuallayers of the EC device, the underlying substrate, etc. may beinspected. Inspection may include, for example, detection of defects inthe EC device and/or edges of the glass.

One or more edge portions of the glass sheet may be removed prior toand/or as part of the patterning process to remove potentialedge-related defects. Additionally, edges may be modified for strength,for example, by removing defects in the glass through mechanical and/oroptical treatment. Separately, defective areas throughout theelectrochromic device may be removed or mitigated by, for example,localized laser heating.

Laser scribes for isolating individual electrodes of EC devices on theindividual electrochromic panes may be added prior to or after cuttingthe panes. Similarly, bus bars for delivering power to the EC deviceelectrodes can be made before or after cutting the panes. A techniqueknown as edge deletion (described below) can also be performed prior toor after cutting the electrochromic panes from the glass sheet.

Insulated glass units (IGU's) are fabricated from the cut electrochromicpanes and optionally one or more of the panes of the IGU arestrengthened. In certain embodiments, strengthening is accomplished bylaminating glass or other reinforcing substrate to the cut panes. In aspecific embodiment, the lamination is performed after the IGU isassembled.

A method of manufacturing one or more electrochromic panes may becharacterized by the following operations: (a) fabricating anelectrochromic device on a glass sheet; (b) defining a cutting patternfor cutting the glass sheet in order to create the one or moreelectrochromic panes, the cutting pattern defined, at least in part, bycharacterizing the glass sheet and/or electrochromic device by one ormore physical features (characteristics) after fabrication of theelectrochromic device; and (c) cutting the glass sheet according to thecutting pattern to create the one or more electrochromic panes. In oneembodiment, characterizing the glass sheet and/or electrochromic deviceincludes identifying the one or more low-defectivity areas, scribing oneor more isolation trenches near one or more edges of the glass sheet,applying a temporary bus bar to the electrochromic device, andactivating the electrochromic device in order to evaluate theelectrochromic device for defectivity. Other methods of identifyingdefects, including areas of non-uniformity, in the EC device includeapplication of polarized light to the glass pane and the like. In oneembodiment, mapping data sets are created based on the one or morelow-defectivity areas and/or non-uniform areas on the electrochromicdevice and the data sets are compared in order to maximize efficient useof the glass sheet.

In some embodiments, electrochromic devices employ all non-penetratingbus bars on the individual electrochromic panes. In this way, moreviewable area is available in the electrochromic panes. The improvedelectrochromic panes may be integrated in IGU's and one or more of thepanes may contain a strengthening feature such as a laminated substrateof glass, plastic or other suitable material.

Certain embodiments relate to methods and apparatus for protecting theedges of IGU's, for example, during handling and/or transport. Edgebumpers are described as well as methods of making edge bumpers,advantages and implementations. Edge bumpers are particularly useful forprotecting IGU's that include annealed glass, but also protect temperedor strengthened glass IGU's.

Various embodiments include laser isolation configurations and relatedmethods of patterning and/or configuring an electrochromic device on asubstrate. In certain embodiments, edge deletion is used to ensure agood seal between the spacer and the glass in an IGU and thus betterprotection of an electrochromic device sealed in the IGU. Certainembodiments include EC devices without isolation scribes. Configurationsfor protecting the EC device edge in the primary seal and maximizingviewable area in an electrochromic pane of an IGU are also described.These embodiments are equally applicable to annealed glass, strengthenedand tempered glass substrates, as well as non-glass substrates.

These and other features and advantages will be described in furtherdetail below, with reference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description can be more fully understood whenconsidered in conjunction with the drawings in which:

FIGS. 1A-B depict process flows describing aspects of fabricationmethods of the invention.

FIGS. 2A-B are schematics depicting aspects of fabrication methods ofthe invention.

FIGS. 2C-D depict aspects of an edge protection device.

FIG. 3A depicts liquid resin lamination of a reinforcing sheet to anIGU.

FIG. 3B depicts a cross section of the laminated IGU as described inrelation to FIG. 3A.

FIGS. 4A-B are cross section schematics depicting two side views of anelectrochromic device.

FIG. 4C is a schematic top view of the electrochromic device describedin relation to FIGS. 4A-B.

FIG. 5A is a cross section schematic showing the device described inrelation to FIGS. 4A-C integrated into an IGU.

FIG. 5B is a cross section schematic showing the IGU as in FIG. 5A,where the EC pane is strengthened by lamination.

FIGS. 6A-B are cross section schematics of an electrochromic device.

FIG. 6C is a schematic top view of the electrochromic device describedin relation to FIGS. 6A-B.

FIG. 7 is a cross section schematic showing the device described inrelation to FIGS. 6A-C integrated into an IGU.

FIG. 8A is a schematic top view of the electrochromic device describedin relation to FIGS. 8B-C.

FIGS. 8B-C are cross section schematics depicting two side views of anelectrochromic device.

FIGS. 9A-B are cross section schematics depicting two side views of anelectrochromic device.

FIG. 9C is a schematic top view of the electrochromic device describedin relation to FIGS. 9A-B.

FIG. 10 depicts a tinted electrochromic pane configured so as not toobscure certain scribe lines as compared with a tinted electrochromicpane configured to obscure all scribe lines.

FIG. 11 is a partial cross section of an IGU showing relativeconfigurations of glass substrates, the electrochromic device, the busbar, the spacer, the primary seal and the secondary seal.

DETAILED DESCRIPTION

For window applications, it is important that electrochromic panes beboth strong and relatively free of defects. Conventionally, glass panesare strengthened by tempering. Unfortunately, the tempering process canintroduce defects in an electrochromic device. Hence, most efforts toproduce electrochromic windows employ a fabrication sequence of firstcutting a glass pane to size, then tempering the glass, and finallyforming the electrochromic device on the tempered window pane. Theelectrochromic device is typically formed by depositing a sequence ofthin layers on one side of the pre-cut and tempered glass pane.Unfortunately, the described sequence of cutting and then forming the ECdevice frequently gives rise to some low quality electrochromic windowsbecause modern fabrication processes often produce one or more visibledefects on an electrochromic device. Of course, the manufacturer mayrefuse to tolerate low quality devices, but rejection of low qualitypanes corresponds to a reduction in yield.

As described herein, various fabrication methods can improve yield andquality. In these methods, initially an electrochromic device isfabricated to substantially cover a glass sheet. Only later is a cuttingpattern for multiple electrochromic panes defined on the glass sheet.The cutting pattern may take into account various considerationsincluding utilization of the sheet, defects in the EC device asfabricated, economic demand for particular sizes and shapes of EC panes,non-uniformity in the device and/or glass sheet, etc.

Frequently, problematic defects occur in only a very small or limitedregion or regions of the glass sheet. Once identified, these regions canbe excluded when defining electrochromic panes in the cutting pattern.In this manner, the cutting pattern may account for high (or low)defectivity regions of the glass sheet. While it is often desirable toprobe the EC device on the large glass sheet to identify and excluderegions of defects, it may sometimes be appropriate to exclude certainregions without probing the device. For example, it is sometimesobserved that defects are concentrated around the perimeter of the largeglass sheet. Therefore it is sometimes desirable to exclude theperimeter region from the pattern of electrochromic panes. In oneexample, between about 1 inches and about 10 inches around the perimeterof the glass sheet is removed after the electrochromic device isfabricated on the glass. In various embodiments, such perimeter regionsare excluded as a matter of course, with the exact amount of excludedperimeter region being based on a knowledge of the quality control (QC)of a well-defined production fabrication process.

Scribes and/or bus bars for the individual panes are provided at somepoint after the cutting pattern is defined. As mentioned, these featuresmay be provided to individual EC panes before and/or after the glasssheet is cut into one or more electrochromic panes according to thepattern. The cutting itself may employ a procedure that improves thestrength of the resulting cut panes. Further, as explained below, theedges may be “finished” to mitigate problems created by cutting.Additionally, in some embodiments, IGU's are fabricated from the cutelectrochromic panes and optionally one or more of the panes of the IGUare strengthened. More details of aspects of the invention are describedbelow and with respect to the Figures.

FIG. 1A depicts a process flow, 100, including a sequence of operationsfor manufacturing one or more electrochromic panes. First a glass sheetis received, see 110. For the purposes of the embodiments describedherein, a large glass sheet is intended to be cut into smaller panes ata later stage of the process. Typically, the panes are intended to beused as windows, so the physical dimensions as well as the optical andmechanical properties of the substrate should be appropriate for theintended window application. In a typical example, the large glass sheetemployed at operation 100 is a piece of glass of between about 3 metersand about 6 meters in length on at least one side. In some cases, theglass is rectangular, being about 3 to 6 meters high and about 1.5 to 3meters wide. In a specific embodiment, the glass sheet is about 2 meterswide and about 3 meters high. In one embodiment, the glass is six feetby ten feet. Whatever the dimensions of the glass sheet, the EC panefabrication equipment is designed to accommodate and process many suchsheets, fabricating EC devices on such sheets, one after another insuccession.

Suitable glass for the glass sheet includes float glass, Gorilla® Glass(a trade name for alkali-aluminosilicate sheet glass available from DowCorning, Corp. of Midland, Mich.) and the like. One of ordinary skill inthe art would recognize that EC devices can be formed on other thanglass substrates. Methods described herein are meant to include othersubstrates besides inorganic glass, for example, plexiglass would alsowork in some instances. For the purposes of simplicity, “glass sheet” isused from herein to encompass all types of window substrate, unlessotherwise specifically qualified.

In one embodiment, the glass sheet is float glass, optionally coatedwith a transparent conducting oxide (TCO) and a diffusion barrier layer.Examples of such glasses include conductive layer coated glasses soldunder the trademark TEC® Glass by Pilkington, of Toledo, Ohio andSUNGATE® 300 and SUNGATE® 500 by PPG Industries of Pittsburgh, Pa. Theglass sheet has a size that is at least equal to the largest EC glasspane contemplated for manufacture. TEC® Glass is a glass coated with afluorinated tin oxide conductive layer. Such glass typically also has adiffusion barrier layer between the TCO and the float glass to preventsodium from diffusing from the glass into the TCO. In one embodiment,the glass sheet does not have a preformed TCO or diffusion barrier onit, for example, in one embodiment the diffusion barrier, a first TCO,an electrochromic stack and a second TCO are all formed in a singleapparatus under a controlled ambient environment (infra). The glasssheet may be heat strengthened prior to fabrication of an electrochromic(EC) device thereon.

Next in the depicted process, an electrochromic (EC) device is preparedon the glass sheet, see 120. In the event that the glass sheet includesa pre-formed diffusion barrier and TCO, then the EC device uses the TCOas one of its conductors. In the event the glass sheet is float glasswithout any pre-formed coatings then typically 120 involves initiallydepositing a diffusion barrier layer, then a transparent conductor(typically a TCO) layer, and thereafter the remainder of the EC deviceis formed. This includes an EC stack having an electrochromic (EC)layer, a counter electrode (CE) layer and an ion conducting (IC) layer.After forming the EC stack, another transparent conductor layer(typically a TCO layer) is deposited as a second conductor (to deliverpower to the EC stack). At this point, the EC device is completed andoperation 120 is concluded. One or more capping layers may also beapplied. In one example, a hermetic layer is applied to keep moistureout of the device. In another example, a low-E (emissivity) coating isapplied.

As is understood by those of skill in the art, many different types ofelectrochromic devices exist, each having its own construction,electrode compositions, charge carrier, etc. Any of these devices may beemployed in the windows described herein. Certain embodiments aredescribed in relation to all solid state and inorganic electrochromicdevices. Such all solid-state and inorganic electrochromic devices, andmethods of fabricating them, are described in more detail in thefollowing U.S. patent application Ser. No. 12/645,111, titled,“Fabrication of Low-Defectivity Electrochromic Devices,” filed on Dec.22, 2009 and naming Mark Kozlowski et al. as inventors; Ser. No.12/645,159, titled, “Electrochromic Devices,” filed on Dec. 22, 2009 andnaming Zhongchun Wang et al. as inventors; Ser. Nos. 12/772,055 and12/772,075, each filed on Apr. 30, 2010, and Ser. Nos. 12/814,277 and12/814,279, each filed on Jun. 11, 2010—each of the latter fourapplications is entitled “Electrochromic Devices,” each names ZhongchunWang et al. as inventors. Each of the above patent applications isincorporated by reference herein for all purposes. In one embodiment,the electrochromic device is a low-defectivity all solid state andinorganic electrochromic device as described in the above applications.In one embodiment, the EC device is manufactured on the glass sheet inapparatus having a controlled ambient environment, that is, an apparatusin which the layers are deposited without leaving the apparatus andwithout, for example, breaking vacuum between deposition steps, therebyreducing contaminants and ultimately device performance. Thismanufacture may include deposition of a diffusion barrier on the glasssheet and the EC device including both electrodes (TCO layers).

As mentioned, inspections may be conducted internally at various pointsin the fabrication flow. For example, one or more of the TCO, EC, IC, CElayers may be inspected during processing. Optical, electrical,chemical, or mechanical inspections may be employed to characterize oneor more parameters of the layers. Such parameters include, for example,optical density, sheet resistance, thickness, defectivity, morphology,and the uniformity of any of these across the glass substrate surface.Separately one or more inspections may be performed after the entire ECdevice is fabricated on the glass sheet surface. As explained elsewhereherein, such inspection may characterize defectivity at regions on thesurface and/or non-uniformities in the EC device.

It would be understood by one of ordinary skill in the art that otherswitchable optical devices besides electrochromic devices may beemployed in the described process. Many such devices are formed aslayers on an underlying substrate. Examples of suitable optical devicesinclude various liquid crystal devices and electrophoretic devicesincluding rotating element and suspended particle devices. Any of thesecan be fabricated or otherwise provided on a large glass sheet and thenprocessed as described herein.

Referring again to FIG. 1A, once the EC device is prepared, a cuttingpattern is defined, see 130. As explained, defining a cutting patternafter depositing the electrochromic device affords considerableflexibility in determining which regions of the fabricated device areused and which are not used in the cut panes. It also, affordsflexibility in determining appropriate sizes of the panes based on theoverall quality of the fabricated electrochromic device. Of course,there are a range of considerations that drive the cutting pattern, andonly some of them pertain to the quality or condition of the asfabricated device. Overall, the characteristics used in defining apattern of EC panes on the glass sheet may include any one or more ofthe following: (1) local defectivity or other measure of local quality(for example, a local non-uniformity in sheet resistance), (2) demandfor particular grades of product (for example some end users specify aparticular grade or quality of EC pane), (3) demand for particular sizesand shapes of products, (4) remake demand (caused by breakages and/orlow yield fabrication of certain types of EC panes), (5) currentinventory of EC device types on the glass sheets and/or individual ECpanes, (6) utilization of the area of the overall glass sheet, and (7)global properties of the EC device (for example, EC device leakagecurrent and electrode (TCO) resistance). A global property might dictatethe appropriate size or grade of the final EC pane(s). For example, highEC device leakage current or high TCO resistance might indicate that theresulting EC panes must be relatively small (for example, not greaterthan about 20 inches). Stated another way, the glass sheets, each with afabricated EC device thereon, are binned based on global properties.

In some embodiments, one or more of the panes defined in the pattern aresized and shaped for residential window applications. In some cases, oneor more of the panes defined in the pattern are sized and shaped forcommercial window applications.

Based on the considerations above, defining a cutting pattern forcutting the glass sheet in order to create the one or moreelectrochromic panes can include characterizing one or more physicalfeatures of the glass sheet and/or electrochromic device afterfabrication of the electrochromic device. In one embodiment,characterizing the one or more physical features include at least oneof: 1) identifying one or more low-defectivity areas on theelectrochromic device, 2) identifying one or more areas ofnon-uniformity in the electrochromic device, 3) identifying one or moreareas where materials used to make the electrochromic device weredeposited on the back side of the glass sheet; 4) identifying one ormore performance characteristics of the electrochromic device; and 5)identifying one or more defects in the glass sheet. Identifying one ormore low-defectivity areas in the electrochromic device is described inmore detail below. Non-uniform areas in the EC device are, for example,areas where, for example, the coloration is not uniform due to variationin thickness of layers of the EC device, variation in properties of thedevice, for example, due to uneven heating during formation of the ECstack, and the like. Non-uniform areas thus may be independent of thenumber of, for example, short related optical defects. It may bedesirable to remove these areas from the cutting pattern or include themin the cutting pattern but identify them as, for example, being areasfrom which a different quality of EC pane will be cut. Also, dependingon the process conditions, materials used to make the electrochromicdevice can be deposited on the back side of the glass sheet due tooverspray. This is undesirable and therefore the presence of backsidedeposition is a useful characteristic of the glass sheet after EC deviceformation. Areas with backside materials may be cleaned to remove theunwanted material and/or these areas are excluded from the cuttingpattern. Performance characteristics of the electrochromic device arealso an important parameter for characterizing the EC device. Asdescribed above, for example, an EC device may be used in different waysdepending on whether it falls into a certain specification category.Identifying one or more defects in the glass sheet is also important,for example, irrespective of the EC device's performance, there may be adefect in the glass sheet, like a bubble or fissure trapped in theglass, which would be excluded from the cutting pattern due to itsundesirable optical properties.

In a specific embodiment, the cutting pattern is defined (operation 130of FIG. 1A) by first detecting and mapping the defectivity of the deviceacross the glass sheet and then excluding or relegating areas of highdefectivity from one or more electrochromic panes in the cuttingpattern. FIG. 1B provides an example process flow for this embodiment.First, as depicted in block 131, the glass sheet's device is scribed inorder to define a usable area, which is typically substantially theentire area of the device as prepared on the glass sheet. The scribingmay serve two purposes. First it electrically isolates the twoelectrodes to provide a functioning device, and second it removesclearly defective portions of the EC stack. In some cases, deposited ECfilms in edge regions of the glass sheet exhibit roll off and/or otherimperfections, and thus present the very real issue of short circuits.To address this problem, the edge regions of the device are isolated orremoved. Techniques for accomplishing this include scribing (presentedin FIG. 1B), edge deleting, or simply removing the glass sheet andassociated device over some fraction of the perimeter.

After the scribe, temporary bus bars are applied, see 132. Then thedevice is activated by application of electrical energy to color orotherwise change the optical properties of the device so that the devicecan be characterized and any defects can be detected, see 133. Thendevice is characterized including identifying any defects and optionallyclassifying the defects as to type and/or severity, see 134. In someembodiments, non-uniformities in the EC device are characterized at thisstage as well. and taken into account when defining the cutting pattern.In some embodiments this characterization includes the glass pane aswell as the EC device on the glass pane. In some examples, theidentification and/or classification is performed by the naked eye. Inother examples, this operation is performed by an automated scanningdevice. In one embodiment, larger short-type visual defects aremitigated by application of electrical or optical energy. In a specificembodiment, such defects are circumscribed by laser ablation to createsmaller pin-hole type defects. These mitigated defects may be includedin the defect count when identifying regions of low defectivity. Inanother embodiment, this ablation or other mitigation is performed afterthe panes are cut from the glass sheet.

It should be understood that activating the EC device and scrutinizingthe device is only one way to detect and identify defects. Other methodsinclude using diffraction, reflection, or refraction of various forms ofelectromagnetic radiation that interact with the EC device, for example,polarized light and/or lock-in infrared (IR) thermography. Lock-in IRthermography is a non-destructive and non-contacting technique for thespatially resolved detection of small leakage currents in electronicmaterials that involves applying a temperature source to the material(in this case the EC device) and detecting leakage current inducedtemperature variations with, for example, an infrared camera. Thus,embodiments include not only activating the EC device to identifydefects, but also may include, or use in the alternative, other methodsof identifying defectivity.

As indicated, the cutting pattern defined on the glass sheet may excludeone or more high-defectivity areas of the electrochromic device providedon the glass sheet. Thus, the fabrication sequences contemplated hereinfrequently involve identifying regions of low or high defectivity priordefining a cutting pattern. In certain embodiments, “low-defectivity”areas are regions of the electrochromic device with fewer than athreshold number or density of defects. Defects may be identified andcharacterized in various ways. In certain embodiments, defects areidentified and/or classified as described in U.S. patent applicationSer. Nos. 12/645,111 and 12/645,159, both previously incorporated byreference.

In certain specific embodiments, only visual defects are considered whendefining a cutting pattern. Visual defects include short-type defectsthat produce a halo when the device is darkened. A halo is a region inthe device where an electrical short across the electrochromic stackcauses an area around the short to drain current into the short andtherefore the area surrounding the short is not darkened. These shortdefects are conventionally treated after fabrication of theelectrochromic device, for example laser circumscribed to isolate them,or ablated directly to “kill” the short, and remove the halo effect,which leaves smaller short-related pinhole defects. In a typicalexample, defects visible to the naked eye are on the order of 100 μm indiameter. In one embodiment, for defects of the size regime greater than100 μm, the total number of visible defects, pinholes and short-relatedpinholes created from isolating visible short-related defects, in alow-defectivity area is less than about 0.1 defects per squarecentimeter, in another embodiment less than about 0.08 defects persquare centimeter, in another embodiment less than about 0.045 defectsper square centimeter (less than about 450 defects per square meter ofelectrochromic pane). Smaller defects, for example defects not visibleto the naked eye (on the order of 40 μm or less), may be tolerable inhigher densities in some embodiments.

The defects that are detected and optionally classified in the glasssheet are mapped, see operation 135 of FIG. 1B. This can be done, forexample, by marking the glass to show where the defects are located oncethe device is inactive, and/or by storing the defect pattern in a memoryas a map. This mapping information is analyzed to identify one or morelow-defectivity regions from which to cut the one or more EC panes, see136. One embodiment of the depicted method defines the cutting patternby (a) creating a first mapping data set based on the one or morelow-defectivity areas on the electrochromic device; (b) creating asecond mapping data set based on another one or more low-defectivityareas on a second electrochromic device on a second glass sheet; (c)comparing the first and second mapping data sets; and (d) defining thecutting pattern using the comparison of the first and second mappingdata sets to maximize efficient use of the glass sheet. For example, themapping may be used to match two compatible EC sheets for use in asingle IGU so that defects in the respective panes do not align. In oneimplementation, the first and second mapping data sets are stored in amemory and (c) and (d) are performed using an appropriate algorithm orother logic. Thus, these mapping data sets and comparisons thereofdefine the most efficient use of the glass sheet's device. For example,mapping data for two glass sheets may indicate that the most efficientuse of the glass would be to cut the two sheets to accommodate differentcustomers' specifications due to defectivity patterns that, if notpresent, would otherwise dictate cutting the sheets according to asingle customer's specifications. Additionally, the logic may definepanes of varying sizes from each glass sheet in order to supplyelectrochromic panes for a variety of window types and end users, forexample, by pane size, defectivity level and the like. Once the one ormore low-defectivity regions are used to define the cutting pattern andprocess flow 130 ends.

FIG. 2A depicts a glass sheet, 200, for example about 3 meters by about2 meters, or about 120 inches by 72 inches, with an EC device (not shownseparately) thereon. In this example, in accord with process flow 100, acutting pattern (as indicated by the dotted lines) is defined forcutting one or more electrochromic panes from glass sheet 200. Dependingupon, for example, the defectivity, demand or other parameters describedabove, the cutting pattern can be regular, such as pattern 202, orirregular, such as pattern 204. Pattern 204 shows, for example, areas206 a and 206 b, which collectively make a strip of glass that is to bediscarded due to, for example, roll off and/or higher defect levels thanthe rest of the glass sheet. These perimeter areas may also be removedbecause of back side contamination of EC device materials due tooverspray. From a single glass sheet, the one or more EC panes can be ofthe same size, or varying size depending on the need.

In some embodiments, prior to cutting the glass sheet, some or all edgesof the sheet may be removed. In some embodiments about 1 to 10 inches ofglass are removed around some, or all, of the glass sheet's perimeter.This edge trimming can be done for a variety of reasons. For example,the quality of the EC device may be inferior around the perimeter of theglass sheet. This low quality around the perimeter may be due to rolloff of the EC device stack, imperfections in the edge of the glass sheet(which can interfere with the EC device fabrication), propagation ofsuch edge defects (e.g. fissures), and cathode dimensions as they relateto the glass sheet dimensions during deposition. Also, deposition ofmaterials on the back side of the glass sheet due to overspray maynecessitate trimming the edges of the glass. Non-uniformities in the ECdevice may occur due to contact of the support pallet during processingof the EC device or non-uniform heating near the edges of the glass.Some of these defects can be appreciated without powering the EC deviceand therefore edge trimming may be performed prior to testing thedevice. Thus edge trimming may be performed as a matter of course or asa result of, for example, performing test runs of the EC formation andfinding that the process parameters require that edge trimming beperformed post device fabrication to remove non-uniformities and/or backside overspray.

Referring again to FIG. 1A, after the cutting pattern is defined for theone or more EC panes, scribes are performed according to the needs ofeach individual EC pane to be cut from the glass sheet, see 140. A moredetailed description of scribes used to fabricate individual EC panes isdescribed below in relation to FIGS. 3A-C. In this process flow, thescribes are made prior to the individual EC panes being cut from theglass sheet. This saves time and resources that would otherwise beneeded in order to scribe the individual panes, since a wide variety ofpane sizes are contemplated as arising from the single glass sheet. Inother embodiments, the scribes are made after the glass sheet is cutinto individual EC panes (infra).

In the depicted example, after the EC devices on the glass sheet havebeen scribed, they are cut from the glass sheet according to the cuttingpattern, see 150. The cutting can be accomplished by any suitableprocess. In some cases, the cutting is accompanied by an edge finishingoperation. Mechanical cutting typically involves scoring the glass witha hard tool, such as a diamond tip on a wheel, followed by snapping theglass along the score line. Thus, mechanical cutting includes “scoring”and breaking. Sometimes the term “scoring” is referred to as “scribing”in the glass window fabrication industry. However, to avoid confusionwith other operations described herein, use of “scribe” will be reservedfor these other operations.

Cutting can produce micro cracks and internal stresses proximate thecut. These can result in chipping or breaking of the glass, particularlynear the edges. To mitigate the problems produced by cutting, cut glassmay be subject to edge finishing, for example, by mechanical and/orlaser methods. Mechanical edge finishing typically involves grindingwith, for example, a grinding wheel containing clay, stone, diamond,etc. Typically, water flows over edge during mechanical edge finishing.The resulting edge surface is relatively rounded and crack-free. Laseredge finishing typically produces a flat, substantially defect freesurface. For example, an initial cut through the glass, perpendicular tothe surface of the glass, may make a substantially defect free cut.However the right angle edges at the perimeter of the glass aresusceptible to breakage due to handling. In some embodiments, a laser isused subsequently to cut off these 90 degree edges to produce a slightlymore rounded or polygonal edge.

Examples of cutting and optional edge finishing processes include thefollowing: (1) mechanical cutting, (2) mechanical cutting and mechanicaledge finishing, (3) laser cutting, (4) laser cutting and mechanical edgefinishing, and (5) laser cutting and laser edge finishing.

In one embodiment, the panes are cut from the glass sheet in a mannerthat actually strengthens and/or improves the edge quality of theresulting panes. In a specific example, this is accomplished using laserinduced scoring by tension. In this method, a gas laser, for example aCO₂ laser with a wavelength of 10.6 μm, is used to heat the surface ofthe glass along a line to produce a compressive stress in the glassalong the line. A cooling device, for example a gas and/or water jet, isused to quickly cool the heated line. This causes a score to form in theglass along the line. The glass is then snapped by, for example, aconventional mechanical breaking device along the score. Using thismethod, the cut edges are extremely clean, that is, there are minimal ifany defects in the glass that can propagate and cause further breakagedue to stresses applied to the pane. In one embodiment, the edges aresubsequently mechanically and/or laser finished to remove the 90 degreeedges to create a more rounded and/or polygonal edge.

Referring again to FIG. 1A, optionally, edge deletion is carried out onthe individual EC panes, see 160. Edge deletion is part of amanufacturing process for integrating the electrochromic device into,for example an IGU, where edge portions of the EC device, for exampleroll off (where layers of the device can make contact due tonon-uniformity near the edge of for example a mask) and/or where a cutis made, are removed prior to integration of the device into the IGU orwindow. In certain embodiments, where unmasked glass is used, removal ofthe coating that would otherwise extend to underneath the IGU spacer isperformed prior to integration into an IGU. Edge deletion is also usedwhen a pane is cut from the glass sheet, as the panes will have ECmaterial running to the edges of the pane. In one embodiment, isolationtrenches are cut and the isolated portions of the EC device on theperimeter of the panes is removed by edge deletion.

Edge deletion can be performed at any stage post formation of the ECdevice in the process flows described. The process of performing edgedeletion is, in some embodiments, a mechanical process such as agrinding or sandblasting process. An abrasive wheel may be employed infor grinding. In one embodiment, edge deletion is done by laser, forexample, where a laser is used to ablate EC material from the perimeterof the pane. The process may remove all EC layers including theunderlying TCO layer or it may remove all EC layers except this bottomTCO layer. The latter case is appropriate when the edge delete is usedto provide an exposed contact for a bus bar, which must be connected tothe bottom TCO layer. In some embodiments, a laser scribe is used toisolate that portion of the bottom TCO that extends to the edge of theglass from that which is connected to the bus bar in order to avoidhaving a conductive path to the device from the edge of the glass, aswell as to protect from moisture encroachment into the IGU along thesame path, as the device layers themselves as they are oftentimespermeable, albeit slowly, to moisture.

In particular embodiments, electromagnetic radiation is used to performedge deletion and provide a peripheral region of the substrate,substantially free of EC device. In one embodiment, described in moredetail below, the edge deletion is performed at least to remove materialincluding the bottom transparent conductor. In one embodiment, the edgedeletion also removes any diffusion barrier. In certain embodiments,edge deletion is performed to the surface of the substrate, e.g. floatglass, and may include removal of some portion of the surface of thesubstrate. Exemplary electromagnetic radiations includes UV, lasers andthe like. For example, material may be removed with directed and focusedenergy of one of the wavelengths including 248,355 nm (UV), 1030 nm (IR,e.g. disk laser), 1064 nm (e.g. Nd:YAG laser), and 532 nm (e.g. greenlaser). Laser irradiation is delivered to the substrate using, e.g.optical fiber or an open beam path. The ablation can be performed fromeither the substrate side or the EC film side depending on the choice ofthe electromagnetic radiation wavelength and, e.g., substrate handlingequipment configuration parameters. The energy density required toablate the film thickness is achieved by passing the laser beam throughan optical lens. The lens focuses the laser beam to the desired shapeand size. In one embodiment, a “top hat” beam configuration is used,e.g., having a focus area of between about 0.2 mm² to about 2 mm². Inone embodiment, the focusing level of the beam is used to achieve therequired energy density to ablate the EC film stack. In one embodiment,the energy density used in the ablation is between about 2 J/cm² andabout 6 J/cm².

During the laser edge delete process the laser spot is scanned over thesurface of the EC device, along the periphery. In one embodiment, thelaser spot is scanned using a scanning F theta lens. Homogeneous removalof the EC film is achieved by overlapping the spots' area duringscanning between about 5% and about 75%. For example, a first laser scanduring a laser edge delete process may be used to remove a portion ofthe EC device. In a second laser scan during the laser edge deleteprocess, the laser spot may overlap with the first scan (i.e., EC devicematerial already removed) by between about 5% and about 75% to aid inachieving homogeneous removal of the EC film. Various scanning patternsmay be used, e.g., scanning in straight lines or curved lines, andvarious patterns may be scanned, e.g., rectangular or other shapedsections are scanned which, collectively, create the peripheral edgedeletion area. In one embodiment, the scanning lines are overlappedbetween about 5% and about 75%. That is, the area of the ablatedmaterial defined by the path of the line previously scanned isoverlapped with later scan lines so that there is overlap. In anotherembodiment, the patterns are overlapped between about 5% and about 50%.That is, a pattern area ablated is overlapped with the area of asubsequent ablation pattern. For embodiments where overlapping is used,a higher frequency laser, e.g. in the range of between about 11 KHz andabout 500 KHz, may be used. In order to minimize heat related damage tothe EC device at the exposed edge (a heat affected zone or “HAZ”),shorter pulse duration lasers are used. In one example, the pulseduration is between about 100 fs (femtoseconds) and about 100 ns(nanoseconds), in another embodiment between about 100 fs and about 10ns, in yet another embodiment between about 100 fs and about 1 ns.

When edge deletion is to be used, it can be done before or after the ECpanes are cut from the glass sheet. In certain embodiments, edgedeletion may be carried out in some edge areas prior to cutting the ECpanes, and again after they are cut. In certain embodiments, all edgedeletion is performed prior to cutting the panes. In embodimentsemploying “edge deletion” prior to cutting the panes, portions of the ECdevice on the glass sheet can be removed in anticipation of where thecuts (and thus edges) of the newly formed EC panes will be. In otherwords, there is no actual edge yet, only a defined area where a cut willbe made to produce an edge. Thus “edge deletion” is meant to includeremoving EC device material in areas where an edge is anticipated toexist.

Referring again to FIG. 1A, after the optional edge deletion, bus barsare applied to the one or more EC panes, see 170. As with edge deletion,the addition of bus bars can be performed after the EC panes are cutfrom the glass sheet or before, but after scribing. By performing thescribe, edge deletion and bus bar application prior to cutting the panesfrom the glass sheet, the associated special handling steps for avariety of EC pane sizes are avoided. That is, performing variousmanipulations and/or component integrations before the individual panesare cut from the glass sheet allows use of apparatus for handling theglass sheets of uniform size for maximum efficiency. However, in oneembodiment, the glass sheet is cut according to 150, then edge deletionis performed according to 160, and thereafter the EC devices are scribedaccording to 140. In this embodiment, edge deletion is performed at theedges of the individual EC panes, and then the scribes are applied. Inanother embodiment, the glass sheet is cut according to 150, then the ECdevices are scribed according to 140, and then edge deletion isperformed according to 160. One advantage of scribing and deleting postcutting is uniformity in the edge deletion process, since only materialfrom the perimeter where actual cut edges (rather than from areas wherean edge is anticipated to exist post cutting) is removed. This methodmay include higher quality control since the edge of the glass can beused as a guide for the edge deletion.

After the panes with fully assembled EC devices are completed, IGU's aremanufactured using the one or more EC panes, see 180. Typically, an IGUis formed by placing sealing separator, for example, a gasket or seal(for example made of PVB (polyvinyl butyral), PIB or other suitableelastomer) around the perimeter of the glass sheet. In some embodiments,the sealing separator includes a metal, or other rigid material, spacerand sealant between the spacer and each glass pane. After the panes aresealed to the spacer, a secondary seal is provided around the outerperimeter of the spacer, for example a polymeric material that resistswater and that adds structural support to the assembly. Typically, butnot necessarily, a desiccant is included in the IGU frame or spacerduring assembly to absorb any moisture. In one embodiment, the sealingseparator surrounds the bus bars and electrical leads to the bus barsextend through the seal. Typically, but not necessarily, the IGU isfilled with inert gas such as argon. The completed IGU can be installedin, for example, a frame or curtain wall and connected to a source ofelectricity and a controller to operate the electrochromic window.

Referring to FIG. 2B, glass sheet 200 is cut according to a cuttingpattern derived, for example, as described herein. In this example four(EC) panes, 208, are produced. Further, in this example, two of panes208 are paired and combined with a sealing separator, 210, to form anIGU, 212. In this example, IGU 212 has two EC panes. Typically, but notnecessarily, the panes are arranged so that EC devices face inside theIGU so as to be protected from the ambient. Electrochromic windowshaving two or more electrochromic panes are described in U.S. patentapplication Ser. No. 12/851,514, filed on Aug. 5, 2010, and entitled“Multipane Electrochromic Windows,” which is incorporated by referenceherein for all purposes. Methods described therein are particularlyuseful for making one or more electrochromic panes for use in multipaneelectrochromic windows. One advantage to such multipane electrochromicwindows is that the likelihood of two defects aligning perfectly, andthus being observable to the end user, is quite small. This advantage isaccentuated when low-defectivity panes are used. In embodiments where,for example, two electrochromic panes are used in a single window, theaforementioned (defect) mapping data sets can be used to further ensurethat defects on individual panes, when registered in an IGU, do notalign. This is yet another criterion that may be considered inpatterning the glass sheet.

In certain embodiments, the glass sheet is up to 5 mm or even up to 6 mmthick (up to ¼ inch). In some embodiments, one or more panes arestrengthened. Referring again to FIG. 1A, optionally, one or both panesof the IGU are strengthened, see 190. For example, in one embodiment,strengthening includes laminating one or more of the panes of the IGUwith, for example, a thicker pane of float glass, a pane of temperedglass, a polymeric pane such as plexiglass, Gorilla® Glass, and thelike. In another embodiment, strengthening includes applying a polymericcoating to one or more panes of the IGU. Examples of such polymericcoatings include ormosil polymeric coatings (epoxy resin, an aminehardener and a silane), sol-gel coatings, acrylic glazes, and othersafety glazes, for example commercially available glazes which meet oneor more impact test standards. Referring again to FIG. 1A, after one ormore panes of the IGU are strengthened, process flow 100 ends.

In some embodiments, an edge bumper is employed to protect the edges ofthe glass after incorporation in the IGU. The protection allows the IGUto be safely transported from manufacturer to installation, for example.A protective edge bumper may be applied to IGU's with or withoutstrengthened panes. Thus, the bumper may be installed to an IGU prior tostrengthening one or both panes, e.g., until such time strengthening isdesired, e.g., as there may be a decision as to which type ofstrengthening desired. Using methods described herein, that choice canbe made at any time post-IGU fabrication. Edge bumpers described hereinallow handling, transport and storage of the IGU's, e.g., until the typeof strengthening, if any, is selected. In one embodiment, the protectivebumper is a U-channel cap which fits over the glass edges around theperimeter of the IGU. It may be made from an elastomeric or plasticmaterial. In one example, it is a vinyl cap. Edge bumpers describedherein are suitable for any IGU to protect the edges of the IGU. Edgebumper embodiments are described in more detail below.

Generally, an edge bumper is configured to protect the edges of theglass in an IGU. This is particularly important when using non-temperedglass. Damage to the glass edges can happen easily if unprotected,because the IGU's are handled, manually and/or mechanically, afterfabrication in the factory, during transport and during installation inthe field. The corners are particularly vulnerable because IGU's aregenerally, though not necessarily, rectangular, and thus the corners aremost easily accidentally bumped into other surfaces causing damage tothe glass edge. Thus, edge bumpers are configured to protect the glassedges of the IGU, in various embodiments, particularly the corners. Asedge bumpers described herein also cover at least some of each face ofan IGU, they impart some protection to the faces of the IGU. Forexample, if an IGU having an edge bumper is laid face down on, or leanedface against, a flat surface, the face of the glass does not touch theflat surface because the edge bumper acts as a spacer between the flatsurface and the face of the glass. Also, if similarly protected IGU'sare stacked horizontally or vertically against each other, only theirrespective edge bumpers make contact with each other, thus the IGU's areprotected from touching each other.

An edge bumper as described herein can be made of a variety ofmaterials, e.g., plastic, rubber, paper, cotton, cardboard, starch, andthe like. In one embodiment, the edge bumper is made of a plastic suchas a polyalkalene, e.g. polyethylene, polypropylene, mixtures thereof,and the like; a polyvinyl, e.g. polyvinyl chloride (PVC), polyvinylfluoride, polyvinylacetate, mixtures thereof, and the like; apolystyrene; a nylon; a rayon; or a polyester. In one embodiment, theedge bumper is made of a biodegradable material, particularly abiodegradable polymer, either synthetic or natural. Generally, it isdesirable for a biodegradable polymer to be non-toxic, have goodmechanical integrity, i.e. keep its shape, and degrade without toxicproducts. Examples of biodegradable polymers include polyesters such aspolyhydroxyalkanoates (PHA's), e.g. 3-hydroxypropionic acid, polylacticacids (PLA's), poly-3-hydroxybutyrate (PHB), polyhydroxyvalerate (PHV),and polyhydroxyhexanoate (PHH); polyanhydrides, polyvinyl alcohol,polybutylene succinate (a synthetic), polycaprolactone (PCL, asynthetic), starch derivatives, cellulose esters, celluloid, and thelike.

In one embodiment, the edge bumper is made of a rubber or a soft pliableplastic, such as PVC, that holds its shape. In this embodiment, the edgebumper has a unitary body shaped as a U- or C-shaped channel in a closedloop configuration that fits over the IGU and conforms to the edges andat least some portion of the faces of the (outermost) glass panes, abouttheir perimeter. In this embodiment, the edge bumper is stretched orotherwise manipulated so that it fits over the IGU, much like a bumperfor a hand held device, such as a smart phone, but only the perimeterportion of each face of the IGU need be covered.

In another embodiment, the edge bumper is made of a plastic, e.g. asdescribed above, where the plastic is rigid or semi-rigid. In oneembodiment, the edge bumper is extruded as a U- or C-shaped channel andthen cut to size to protect an IGU. In one embodiment, the extrudedchannel is cut as individual pieces that each protect one side of anIGU. In one embodiment, the ends of the individual channel pieces arecut at an angle so that when all four pieces are fitted onto the IGU,they fit closely together at the edges so as to protect the corners ofthe IGU. In one embodiment, the channel is extruded as a unitary memberthat is folded around the IGU after extrusion. One such embodiment isdescribed in relation to FIGS. 2C and 2D.

FIG. 2C depicts a perspective of a portion of channel, 214, that can beused to form an edge bumper as described herein. Channel 214 has agenerally U-shaped cross section, which is narrower at the opening ofthe channel, see dimension A (cross section of channel 214, lower leftof FIG. 2C), than at the base of the channel, see dimension B. DimensionA is smaller than the thickness of the IGU to which channel 214 is to beapplied in order to form the edge bumper. Because channel 214 isgenerally thin, e.g., the material comprising channel 214 is betweenabout 1 mm and about 10 mm thick, typically between about 1 mm and about5 mm thick, the IGU can be squeezed into the channel through dimension Aand seat into the bottom of the channel, as depicted in the lower rightcross section of FIG. 2C. The edges of glass panes, 208 (see also FIG.2B), of IGU 212 (spacer 210 depicted with primary and secondary sealantaround it, and desiccant inside it), may rest against the base ofchannel 214 and are protected by it. Channel 214 may have a lip, 216which allows more facile entry of the IGU into the channel, e.g., thechannel is guided onto the edge of the IGU, facilitated by the opennature of the lip on the other side of the opening of channel 214. Thechannel may also have at least some portion of its interior surface(surface inside the channel) that is configured to contact the faces ofthe glass panes of the IGU in a substantially parallel fashion. In thisexample, channel 214, has a portion, 218, of its inner surface thatmates with the glass of the IGU in order to achieve better hold onto theglass. By virtue of the rigidity of channel 214 and dimension A, thereis a spring action so that channel 214 is held onto the glass withoutslipping off. In one embodiment, channel 214 is made of a rigid orsemi-rigid plastic material, e.g., a biodegradable polymer.

FIG. 2D shows aspects of a method of making an edge bumper fromchanneled material, e.g., channel 214 as described in relation to FIG.2C, and installing the edge bumper. For example, IGU 212 is fabricated.A portion of channel 214 is extruded; the length of the portion isapproximately the length of the perimeter of IGU 212. A series ofnotches, 220, are cut into channel 214. These notches are cut atpositions where the edge bumper will be folded to accommodate thecorners of IGU 212. The bottom portion of the channel (see FIG. 2C) isleft intact so that the corners of the IGU glass will be protected whenthe channel is folded around the edges of the IGU. The notches allowthis folding, while the material remaining at the bottom of the channelforms the vertex of the fold and protects the corners of the IGU onceapplied thereto. The notches thus delineate sub-portions of a unitaryportion of channel 214; each sub-channel will each fit along an edge ofIGU 212. One embodiment is an edge bumper as described, having at leastthree notches for folding to accommodate corners of the IGU. If onlythree notches are used, the ends of the bumper will meet at the cornerthat is not covered by a notched/folded section of the bumper. Theseends may be taped to aid in securing them during handling. In theembodiment depicted in FIG. 2D, there are four notches, so that the endscan meet along a side of the IGU. This protects all the corners equally,as each is protected by a notched section of the channel.

In one embodiment, the dimensions of the IGU are sent to an extrusionmachine (or a machine that dispenses channel previously extruded) sothat notches 220 can be cut in the appropriate positions in theextrusion as it is dispensed. This saves valuable time and money,because the edge bumper is manufactured using the dimensions of the IGUfrom the apparatus that makes the IGU, only after the IGU is actuallyfabricated and specifically to fit the IGU coming off the IGUfabrication line. Thus, there is no need to fabricate a large stock ofedge bumpers in anticipation of making a number of IGU's. By usingbiodegradable material for the edge bumper, there is less worry aboutdisposal in the field, e.g., during installation of the IGU into abuilding.

Referring again to FIG. 2D, starting from the top and moving downward ofthe figure, edge bumper 214, of the appropriate length, is notchedappropriately and is fitted onto IGU 212 along one edge. The twoadjoining sub-portions of bumper 214 are fitted along the edgesorthogonal to the first edge fitted with channel 214 as depicted by thedotted arrows. Finally, the two remaining sub-portions are folded tocover the edge of IGU 212 opposite the first edge. This is an efficientway of applying channel 214 to the IGU because it requires only twofolding operations to cover four edges of the IGU. These operations canbe done manually or in automated fashion, e.g., where a suction cupdevice holds, rotates and translates the IGU appropriately and othermeans, e.g. mechanical arms, grabbers, posts, walls, rollers and/orsimilar devices, are used to facilitate folding operations.

As noted in FIG. 2D, tape may be applied across the ends of channel 214in order to ensure that it stays on IGU 212 until its removal isdesired. In this example, a piece of tape is applied to one side of theIGU, over the edge bumper, and onto the other side of the IGU so thatthe edge bumper is held to the glass on both sides of the IGU.

One of ordinary skill in the art would appreciate that the foldingoperations can be performed in a variety of ways. Also, the channel maybe applied to the IGU as it is extruded and notched, e.g., rather thancutting the full length, notching and then applying.

In one embodiment, the bumper is applied as a hot or warm extrusion thatis pliable during application to the IGU. The pliable extrusion ismolded to each edge of the IGU, e.g. as the IGU is rotated in a planeparallel with the face of the glass panes of the IGU. At the corners,when applying the pliable extrusion and molding it to the edge of theIGU, the pliable material is folded, on each of the respective faces ofthe glass panes, to accommodate the extra material that occurs whenfolding a material around a corner. In one embodiment, the pliableextrusion is cut in a length sufficient so that the ends of the unitarypiece of pliable extrusion can meet and/or overlap and bond to eachother. In another embodiment, the pliable extrusion is cut in a lengthsufficient so that the ends of the unitary piece of pliable extrusion donot meet, but rather a small gap remains (e.g. as depicted in FIG. 2D,the gap in channel 214 (covered by the tape)) in order to aid inremoving the pliable material. The pliable material may harden to someextent in order to hold to the glass and also to aid in removal, i.e.the material can be peeled off without significant, or any, ripping ortearing.

One embodiment is a method of manufacturing an insulated glass unit(IGU), the method including: (a) fabricating an electrochromic device ona transparent substrate to create an electrochromic window pane; (b)fabricating an insulated glass unit (IGU) comprising the electrochromicwindow pane; and (c) applying an edge bumper to the IGU. In oneembodiment, the bumper includes a U-channel cap which fits over theglass edges at the perimeter of the IGU. In one embodiment, the bumperincludes an elastomeric or plastic material. In one embodiment, themethod further includes transporting the IGU, with the bumper applied,from a manufacturer to an installer. In one embodiment, the methodfurther includes strengthening the electrochromic window pane prior toinstalling the bumper. In one embodiment, strengthening includeslaminating a second pane to the electrochromic window pane while in theIGU. In one embodiment, applying the edge bumper to the IGU includesfolding an extruded material, from which the U-channel is comprised,around the perimeter of the IGU. In one embodiment, the extrudedmaterial is notched to accommodate folding at the corners of the IGU. Inone embodiment a piece of adhesive tape (e.g. masking tape) is used tosecure the edge bumper to the IGU. In one embodiment, the extrudedmaterial is biodegradable.

Another embodiment is a method of manufacturing an edge bumper for anIGU, the method including: 1) receiving dimensions of the IGU from aunit that fabricated the IGU, 2) cutting a U-channel material to theappropriate length to cover the perimeter of the IGU, and 3) notchingthe U-channel material appropriately to accommodate folds in theU-channel material at the corners of the IGU. In one embodiment, theU-channeled material has four notches and five sub-portions. Anotherembodiment is a method of applying the aforementioned notched U-channelmaterial including: 1) applying the central sub-portion of the notchedU-channel material over one edge of the IGU, 2) folding the adjoiningtwo sub-portions over the two orthogonal edges to the one edge, and 3)folding the remaining two sub-portions over the remaining edge, oppositethe one edge. In one embodiment, the method is performed in the order:1, 2 and then 3. Another embodiment is an apparatus configured to carryout the operations 1, 2 and 3 in an automated fashion. In oneembodiment, the method further includes securing the U-channel to theIGU with a piece of adhesive tape.

One embodiment is an apparatus configured to carry out the operationsdescribed herein with relation to edge bumper manufacture, and/orinstallation on an IGU.

The embodiments described herein that relate to edge bumpers aredescribed in terms of protecting rectangular IGU's. One of ordinaryskill in the art would appreciate that other shapes for IGU's arepossible, and the edge bumpers, methods of manufacture and applicationthereof apply to other IGU shapes. For example a trapezoidal IGU,triangular or other polygonal IGU would accommodate the edge bumpersdescribed herein, e.g., a rigid bumper would need only have theappropriate number of notches to fold around the polygonal IGU. Inanother example, a round or oval IGU would accommodate an edge bumperwith, e.g., many notches if made of a highly rigid material (in order tomake the curves without breaking the bumper) or a more flexible materialcan be used with no notches.

Laminating an EC pane with a reinforcing substrate (or pane) afterincorporation into an IGU has many benefits. For example, laminationafter the EC pane is assembled in an IGU protects the EC device duringthe lamination process and provides ease of handing. This isparticularly true if the EC device is on an inner facing surface of theIGU, that is, in the interior insulating region of the IGU, becauselamination processes involve contacting the outer surfaces of the glasspanes making up the lamination structure under relatively harshconditions. Under such conditions, the EC device would be damaged if itwas located on the outer surface of a lamination structure. The IGU thusprotects the device during lamination. If the EC device is located on anouter facing surface of glass on the IGU, lamination of the EC panewould require lamination directly onto the EC device with thereinforcing pane and/or the adhesive used to attach it (the laminationpane). While lamination can be conducted without damaging the EC device,this approach has some downsides. Most notably, the IGU would be a lesseffective thermal insulator because radiation is blocked only at theinterior of the IGU. Further, the exposed edges of the EC device,located around the perimeter of the IGU, may provide an ingress pointfor moisture after installation.

Many different lamination processes can be employed in the disclosedembodiments. Examples include roll pressing and autoclaving, vacuumbagging, and liquid resin lamination, each of which is well known in thewindow fabrication industry. In one embodiment, liquid resin laminationis used to strengthen an EC pane after it is incorporated into an IGU.

FIG. 3A schematically depicts aspects of a process flow for liquid resinlamination of an IGU, 300. In FIG. 3A, IGU 300 is drawn in less detailthan for example IGU 212 described in relation to FIG. 2B. In thisexample, IGU 300 has an EC pane and a non-EC pane. Typically, doublesided tape, 305, is applied to a perimeter region of the EC pane. A gap,315, is left in the perimeter tape, for example, in a corner of thepane. A reinforcing pane, 310, is applied to the double-sided tape, sothat a triple pane (see also FIG. 3B, in this example, the reinforcingpane is laminated to the EC pane of the IGU, and there is also thenon-EC pane of the IGU which is not part of the laminate) structure,320, is formed. A liquid resin, 325, is introduced, for example from thebottom as depicted, in the volume formed between the EC pane andreinforcing pane 310. This can be accomplished, for example, by leavinga small portion of the backing of the tape on when pane 310 is appliedto the tape and registered with the EC pane. A dispensing nozzle, in theshape of a thin blade, is inserted in between pane 310 and the portionof the tape with the backing remaining. After the resin is introducedinto the volume and the blade removed, the remaining tape backing isremoved so that the only means of exit for the resin is gap 315. Asindicated by the curved and dotted heavy arrows, unit 320 is thenrotated so that the liquid resin 325 flows toward gap 315 (as indicatedin the lower left diagram by the heavy dotted arrow downward). Theappropriate amount of resin is introduced into the volume so that whenthe resin covers the entire area between the panes and within the tape,the panes are substantially parallel to each other. Once the volume isfilled with resin, the resin is cured, for example, via heating, acatalyst and/or exposure to UV irradiation to form a strong bond betweenthe panes. In the final assembly, as depicted in the lower right of FIG.3A, the cured resin has the desired optical, mechanical and otherproperties of the lamination. Using liquid resin lamination impartsminimal if any stress on the EC pane during lamination.

FIG. 3B is a cross section showing more detail of the final assembly320. The IGU portion, 300, includes a first pane, 301, and an EC pane,302, which includes an EC device, 303, thereon. Panes 301 and 302 areseparated by a sealing separator, 304, which spans the perimeter of thepanes and has seals between it and each pane. An interior space, 330, isdefined by the panes and the sealing separator. Tape 305 lies between(and proximate to the perimeter) of the face of the EC pane outside ofthe IGU's interior space and pane 310. Inside the volume created betweenthe EC pane and pane 310 is the cured resin, 325.

Because resin based lamination relies on a sheet or film of resinsandwiched between the two glass panes to be laminated, choice of resintype can impart an optical characteristic to the window unit. In certainembodiments, the resin may contain additives that impart a desiredoptical property to the resulting laminate. Examples of such opticalproperties include color, opacity, scattering and reflectivity. In aspecific example, the resin imparts a blue color. This can beparticularly beneficial when used with some EC devices that have anaturally yellowish tint. The optical property can be imparted by addingdyes, pigments, scattering particles, metallic dust, etc. to the liquidresin prior to introduction into volume for lamination. In certainembodiments, the blue color is achieved as a result of a chemicalreaction that takes place after the resin is introduced into the volumebetween the panes. For example, the reaction may be catalyzed by thesame energy or reagent that catalyzes the curing of the resin. Inanother embodiment, the resin changes to a blue color after curing, forexample, by exposure to normal ambient lighting and/or specificirradiation and/or heating post cure.

Particular examples of electrochromic panes are described with referenceto FIGS. 4A-C. FIG. 4A is a cross-sectional representation of anelectrochromic pane, 400, which is fabricated starting with a glasssheet, 405, for example as outlined in process flow 100. FIG. 4B showsthe cross sectional view from another side of EC pane 400, and FIG. 4Cshows a top view of EC pane 400 (FIG. 4A is the view from the right orleft side as depicted in FIG. 4C; and FIG. 4B is the view from thebottom side looking up as depicted in FIG. 4C). FIG. 4A shows theindividual electrochromic pane after it has been cut from the glasssheet, edge deleted, laser scribed and bus bars have been attached. Theglass pane, 405, has a diffusion barrier, 410, and a first transparentconducting oxide (TCO) 415 on the diffusion barrier. The TCO layer 415is the first of two conductive layers used to form the electrodes of theelectrochromic device fabricated on the glass sheet. In this example,the glass sheet includes underlying glass and the diffusion barrierlayer. Thus in this example, the diffusion barrier is formed, then thefirst TCO, then the EC stack, and then the second TCO. In oneembodiment, the electrochromic device (EC stack and second TCO) isfabricated in an integrated deposition system where the glass sheet doesnot leave the integrated deposition system at any time duringfabrication of the stack. In one embodiment, the first TCO layer is alsoformed using the integrated deposition system where the glass sheet doesnot leave the integrated deposition system during deposition of the ECstack and the (second) TCO layer. In one embodiment, all of the layers(diffusion barrier, first TCO, EC stack and second TCO) are deposited inthe integrated deposition system where the glass sheet does not leavethe integrated deposition system during deposition.

After formation of the EC device, edge deletion and laser scribes areperformed. FIG. 4A depicts areas 440 where the device has been removed,in this example, from a perimeter region surrounding the laser scribetrenches, 430, 431, 432 and 433, which pass through the second TCO andthe EC stack, but not the first TCO, are made to isolate portions of theEC device, 435, 436, 437 and 438, that were potentially damaged duringedge deletion from the operable EC device. In one embodiment, laserscribes 430, 432, and 433 pass through the first TCO to aide inisolation of the device (laser scribe 431 does not pass through thefirst TCO, otherwise it would cut off bus bar 2's electricalcommunication with the first TCO and thus the EC stack). The laser orlasers used for the laser scribes are typically, but not necessarily,pulse-type lasers, for example diode-pumped solid state lasers. Forexample, the laser scribes can be performed using a suitable laser fromIPG Photonics (of Oxford Mass.), or from Ekspla (of Vilnius Lithuania).Scribing can also be performed mechanically, for example, by a diamondtipped scribe. One of ordinary skill in the art would appreciate thatthe laser scribes can be performed at different depths and/or performedin a single process whereby the laser cutting depth is varied, or not,during a continuous path around the perimeter of the EC device. In oneembodiment, the edge deletion is performed to the depth below the firstTCO. In another embodiment, a second laser scribe is performed toisolate a portion of the first TCO, for example as depicted in FIGS.4A-C, near the edge of the glass pane from that toward the interior. Inone example this scribe is at least along the edge where bus bar 2 isapplied to the first TCO, between bus bar 2 and the edge.

After laser scribing is complete, bus bars are attached. Non-penetratingbus bar (1) is applied to the second TCO. Non-penetrating bus bar (2) isapplied to an area where the device was not deposited (for example froma mask protecting the first TCO from device deposition), in contact withthe first TCO or in this example, where edge deletion was used to removematerial down to the first TCO. In this example, both bus bar 1 and busbar 2 are non-penetrating bus bars. A penetrating bus bar is one that istypically pressed into and through the EC stack to make contact with theTCO at the bottom of the stack. A non-penetrating bus bar is one thatdoes not penetrate into the EC stack layers, but rather makes electricaland physical contact on the surface of a conductive layer, for example,a TCO.

The TCO layer's can be electrically connected using a non-traditionalbus bar, for example, screen and lithography patterning methods. In oneembodiment, electrical communication is established with the device'stransparent conducting layers via silk screening (or using anotherpatterning method) a conductive ink followed by heat curing or sinteringthe ink. Advantages to using the above described device configurationinclude simpler manufacturing, for example, less laser scribing thanconventional techniques which use penetrating bus bars, and the factthat the EC device colors to, and under, bus bar 1 (unlike conventionalmethods which cut an isolation trench through the device when bus bar 1is a penetrating type bus bar), which provides a larger coloration area.Penetrating bus bar's can be used, for example in place ofnon-penetrating bus bar 1, but this will sacrifice colorable area andwould necessitate a scribe through the first TCO, prior to fabricationof the EC stack on the glass. One embodiment contemplates performingthis first scribe for the one or more EC devices on the glass sheetprior to fabrication of the EC device thereon. In such embodiments, theremainder of the method flow, for example as described in relation toFIGS. 1A and 1B, remains analogous.

As described above, after the bus bars are connected, the device isintegrated into an IGU, which includes, for example, wiring the bus barsand the like. In some embodiments, one or both of the bus bars areinside the finished IGU, however in one embodiment one bus bar isoutside the seal of the IGU and one bus bar is inside the IGU. FIG. 5Adepicts a cross section of the EC pane as described in relation to FIGS.4A-C integrated into an IGU, 500. A spacer, 505, is used to separate ECpane 400 from another pane, 510. The second pane 510 in this example isa non-EC pane, however the invention is not so limited. Pane 510 canhave an EC device thereon and/or one or more coatings such as low-Ecoatings and the like. Between spacer 505 and, in this example, thefirst TCO of EC device 400, is a primary seal, 515. This seal is alsobetween separator 505 and the second glass pane. Around the perimeter ofseparator 505 is a secondary seal, 520 (bus bar wiring traverses theseal for connection to controller). These seals aid in keeping moistureout of the interior space, 550, of the IGU.

FIG. 5B depicts IGU 500 after lamination with a reinforcing pane, 530.In this example a liquid resin lamination was used, and thus, curedresin, 535, lies between the reinforcing pane and the glass of the ECpane. Although not depicted, one of ordinary skill in the art wouldappreciate that if glass 2 also had an EC device thereon, it could alsobe laminated. One embodiment is an IGU including two EC panes separatedby an interior space, in one example both EC devices are in the interiorspace of the IGU, where both EC panes are reinforced. In one embodiment,the EC panes are reinforced with liquid resin lamination as describedherein. In other embodiments, one or both of the EC panes are reinforcedor strengthened by applying a coating as described herein.

FIGS. 6A and 6B are like FIGS. 4A and 4B, showing a construction, 600,which is an EC device fabricated on a glass substrate. FIG. 6C is a topview showing that FIG. 6A depicts cross-section X-X′, and FIG. 6Bdepicts view Y-Y′. In this example, areas 640 represent where the devicehas been removed, in this example, from a perimeter region surroundinglaser scribe trenches, 630, 631, 632 and 633. In this example, laserscribes 630, 632 and 633 pass through the second TCO, the EC stack andthe first TCO, and isolate the operable EC device, portions of the ECdevice, 635, 637 and 638, that were potentially damaged during edgedeletion. Laser scribe 631 is made through the second TCO and the devicestack, but not the bottom TCO, as this serves as the lower conductor inelectrical communication with bus bar 2. In this example, the EC stack,the first TCO and the diffusion barrier were removed in the edgedeletion areas 640. This is an example of edge deletion performed to adepth below the first TCO. By removing the lower TCO, and optionally thediffusion barrier, the EC device is more effectively isolated from theambient when sealed in an IGU, that is, the edges of the TCO (which ispart of the EC device) are not exposed to the ambient. Also, the primaryseal and secondary seal may be more reliable as they are not subject todelamination of the diffusion barrier or TCO, but rather are madebetween the spacer and the glass substrate. As depicted in FIG. 6C, edgedelete area 640 spans the perimeter of the EC device, around the outerperimeter of the glass. FIG. 7 shows a cross-section as in FIG. 6Aincorporated into an IGU, 700. A spacer, 705, is used to separate ECpane 600 from another pane, 710. The second pane 710 in this example isa non-EC pane, however the invention is not so limited. Pane 710 canhave an EC device thereon and/or one or more coatings such as low-Ecoatings and the like. Between spacer 705 and, in this example, theglass substrate of EC device 600, is a primary seal, 715. This seal isalso between separator 705 and the second glass pane. Around theperimeter of separator 705 is a secondary seal, 720 (bus bar wiringtraverses the primary seal for connection to controller). These sealsaid in keeping moisture out of the interior space, 750, of the IGU.Analogous to that depicted in FIG. 5B, IGU 700 can be laminated toanother glass sheet using, e.g., a cured resin.

FIG. 8A depicts a top view of a construct, 800, which includes an ECdevice, 805, on a glass sheet, similar to 600 as depicted in FIG. 6C,but where there are no isolation trenches (scribes) formed in order toisolate portions of EC device 805 due to, e.g., defects in the deviceabout the perimeter due to edge deletion. In this example, edge deletionareas, 840, about the perimeter, are formed using a laser technique thatleaves clean edges about the EC device and thus further isolationtrenches are not necessary (e.g., using lasers, power densities, spotconfigurations etc. as described herein). With the advent of tightercontrol of laser ablation technology, e.g. improved computer algorithms,power supplies, laser focusing and tracking methods, such clean edgedeletion is possible without the need for additional laser isolationtrenches. One embodiment is an EC device fabricated on a transparentsubstrate where a perimeter portion (edge delete) of the EC device isremoved by laser ablation. In one embodiment, the perimeter portion isbetween about 1 mm and about 20 mm wide, in another embodiment betweenabout 5 mm and about 15 mm wide, and in yet another embodiment betweenabout 8 mm and about 10 mm wide. In one embodiment, there are noadditional isolation trenches, laser or other, made during fabricationof the device.

FIG. 8B depicts cross-section Z-Z′ and FIG. 8C depicts view W-W′.Devices fabricated in this manner do not need isolation scribes.Specifically, an EC device is fabricated on a glass substrate, e.g.including all the layers depicted. The edge delete is performed. Also, aportion of the EC device, down to the lower electrode, transparent inthis example, is removed in order to create a “landing” for bus bar 2.This landing area is sometimes referred to as a “bus bar pad expose” or“BPE,” where a portion of the lower conductor is exposed so that a busbar can be formed thereon. Formation of the edge delete area and BPE canbe performed in any order. In one embodiment, the edge deletion isperformed before the BPE. Various aspects of BPE are described in moredetail below.

As mentioned above, in various embodiments, a BPE is where a portion ofan EC device, down to the lower electrode, e.g. a transparent conductingoxide, is removed in order to create a surface for a bus bar to beapplied and thus make electrical contact with the electrode. The bus barapplied can be a soldered bus bar, and ink bus bar and the like. A BPEtypically has a rectangular area, but this is not necessary; the BPE maybe any geometrical shape or a random shape. For example, depending uponthe need, a BPE may be circular, triangular, oval, trapezoidal, andother polygonal shapes. The shape may be dependent on the configurationof the EC device, the substrate bearing the EC device (e.g. an irregularshaped window), or even, e.g., a more efficient laser ablation patternused to create it. In one embodiment, the BPE substantially spans oneside of an EC device and is wide enough to accommodate the bus bar withspace at least between the EC device stack and the bus bar. In oneembodiment, the BPE is substantially rectangular, the lengthapproximating one side of the EC device and the width is between about 5mm and about 15 mm, in another embodiment between about 5 mm and about10 mm, and in yet another embodiment between about 7 mm and about 9 mm.As mentioned, a bus bar may be between about 1 mm and about 5 mm wide,typically about 3 mm wide.

The BPE is typically, but not necessarily, made wide enough toaccommodate the bus bar's width and also leave space between the bus barand the EC device (as the bus bar is only supposed to touch the lowerelectrode). The bus bar width may exceed that of the BPE (and thus thereis bus bar material touching both lower conductor and glass), so long asthere is space between the bus bar and the EC device. In embodimentswhere the bus bar width is accommodated by the BPE, that is, the bus baris entirely atop the lower conductor, the outer edge, along the length,of the bus bar may be aligned with the outer edge of the BPE, or insetby about 1 mm to about 3 mm. Likewise, the space between the bus bar andthe EC device is between about 1 mm and about 3 mm, in anotherembodiment between about 1 mm and 2 mm, in another embodiment about 1.5mm. Formation of BPE's is described in more detail below, with respectto an EC device having a lower electrode that is a TCO. This is forconvenience only, the electrode could be any suitable electrode,transparent or not.

To make a BPE, an area of the bottom TCO needs to be cleared ofdeposited material so that a bus bar can be fabricated on the BPE. Inone embodiment, this is achieved by laser processing which selectivelyremoves the deposited film layers while leaving the bottom TCO exposedin a defined area at a defined location. In one embodiment, theabsorption characteristics of the bottom electrode and the depositedlayers are exploited in order to achieve selectivity during laserablation, that is, so that the EC materials on the TCO are selectivelyremoved while leaving the TCO material intact. In certain embodiments,an upper portion of the TCO layer is also removed in order to ensuregood electrical contact of the bus bar, e.g., removing any mixture ofTCO and EC materials that might have occurred during deposition. Incertain embodiments, when the BPE edges are laser machined so as tominimize damage at these edges, the need for an isolation scribe line(e.g. see description above in relation to FIGS. 8A-C) to limit leakagecurrents can be avoided—this eliminates a process step, while achievingthe desired device performance results.

In certain embodiments, the electromagnetic radiation used to fabricatea BPE is the same as described above for performing edge deletion. The(laser) radiation is delivered to the substrate using either opticalfiber or the open beam path. The ablation can be performed from eitherglass side or the film side depending on the choice of theelectromagnetic radiation wavelength. The energy density required toablate the film thickness is achieved by passing the laser beam throughan optical lens. The lens focuses the laser beam to the desired shapeand size, e.g a “top hat” having the dimensions described above, in oneembodiment, having an energy density of between about 0.5 J/cm² andabout 4 J/cm². In one embodiment, laser scanning for BPE is done asdescribed above for laser edge delete.

Using the methods described above, where edge delete and BPE are usedwithout additional isolation scribes, the need for masks is obviated,i.e., roll off and/or damaged or unwanted material around the perimeterof the EC device is removed in the edge delete. One of skill in the artwould appreciate that if the substrate is held in position by, e.g.,clamps or other means, portions of the substrate may not be coated. Whatis meant is that no masks for patterning the device are necessary. Also,because the edge delete makes a clean edge on the device, there is noneed for isolation scribes to further “clean up” the edges, e.g. wherean edge deletion does not remove material to form a clean edge where theindividual layers of the EC device are exposed. A further advantage tothese methods is that there is no need for patterning between depositionof individual layers of the EC device. For example, onto a substrate arecoated successive layers of material that form the EC device. Once theEC device layers are fabricated, the edge delete and BPE are performed.These methods are particularly useful for “coat n cut” technology, asdescribed herein, i.e. where the EC device is coated on annealed glassor other substrate that can be cut after the EC device is deposited. TheEC device is coated, e.g. as described herein, and the glass substrateis cut according to desired size as described herein. Then the edgedelete and BPE are performed. Finally the bus bars are attached.Optionally, a sealant coating can be applied over the entire constructto hermetically seal the device, including the bus bars and the sides ofthe device where the edges of the individual layers are exposed. With orwithout such sealant coating, the device may be hermetically sealed inan IGU, e.g., as described in FIG. 5A, 5B or 7.

One embodiment is a method of fabricating an EC device including: 1)coating a substrate with the EC device without the use of patterning ofthe individual layers of the EC device, 2) edge deleting a perimeterportion of the device about the perimeter of the substrate, and 3)removing a portion (BPE) of the EC device to expose the lower conductinglayer; wherein the perimeter portion (edge delete) is between about 1 mmand about 20 mm wide, between about 5 mm and about 15 mm wide, orbetween about 8 mm and about 10 mm wide.

As described in various embodiments herein, sometimes it is desirable tofabricate an EC device using one or more laser isolation scribes. FIG.9A depicts cross-section U-U′ and FIG. 9B depicts view V-V′ as indicatedin FIG. 9C, of an EC lite, 900, which includes an EC device on a glasssheet. Referring to FIG. 9A, this construct is prepared starting with aglass substrate having a diffusion barrier and a first transparentconductive oxide deposited thereon. Masks may be used to protect aperiphery region, 940, or area 940 may be formed by edge deletion asdescribed herein. Before deposition of the EC stack, isolation scribe,920 is formed, which bifurcates the diffusion barrier/TCO layers intotwo regions (see FIG. 9C). Then the EC stack and top TCO are formed.Depending upon the deposition parameters, e.g. sputter deposition, theEC stack and top TCO layers may have roll off material, 930, about theperimeter of the area defined by mask or edge delete procedure, on topof the first TCO. Isolation scribe 950 is formed parallel, but on theopposite side of the device from trench 920. In one embodiment, a BPE isused and there is no need for isolation scribe 950. Referring to FIG.9B, isolation trenches, 960 and 970, are also formed. Isolation trenches950, 960 and 970 are made to isolate the bulk device from the roll off930 about three sides of the perimeter. In this example, scribes 960 and970 pass through first (lower) TCO and diffusion barrier, while scribe950 does not penetrate the first TCO. Bus bar 1 is applied as anon-penetrating bus bar, while bus bar 2 is a penetrating type (e.g asoldered type) bus bar, which penetrates through the second TCO and ECstack to make electrical connection with the bottom (first) TCO. In oneembodiment, when a BPE is used to remove a portion of material 930 wherethe bus bar to the lower electrode will be placed (bus bar 2 in thisexample) a non-penetrating bus bar is used. In a particular embodiment,only portion 930 a (see FIG. 9C) is removed in the BPE (the portions of930 on the outside of scribes 960 and 970 are left intact). The ECdevice functions properly because any short circuiting that might occurdue to the roll off 930 touching the first (bottom) TCO is cut off byisolation trenches 920, 960 and 970. Isolation trench 920 is effectivebecause it is filled with EC stack materials and thus is much lesselectrically conductive than the TCO. Isolation trench 950 breakselectrical connection between bus bars 1 and 2 via the top TCO.

Electrochromic lites such as 900 are sometimes preferred because, e.g.,one can deposit the EC device on the glass substrate without having tonecessarily use masks. For example, the layers of the EC device are laiddown on the glass substrate without any mask or edge delete. Then edgedeletion is used to remove material from a periphery portion of theglass substrate. Isolation trenches are used to isolate any remainingroll off and no BPE is needed since a penetrating bus bar is used atopone of the roll off areas isolated by one of the trenches (e.g. 950). Asmentioned, however, one embodiment is a device as described in relationto FIGS. 9A-C, but having a BPE rather than isolation scribe 950.

It is noteworthy that the isolation trenches as described above do notcolor or tint when the EC device is colored. This is because thetrenches either contain no EC device material or, as in trench 920, thedevice material may be compromised in the trench and/or there is nobottom TCO to form a viable device in the region of the trench. If thesetrenches are not obscured from the viewable area of the windowcontaining the EC lite, then when the window is colored, the isolationtrenches will appear as bright lines against the colored background ofthe tinted window. This high contrast is possible because EC windows cantint to block nearly all transmission through the window, nearly opaque.The contrast between the scribe line and the tinted device isundesirable from an aesthetic standpoint. Note, for example, in thedevice depicted in FIGS. 9A-C, isolation trenches 920 and 950, proximatethe bus bars, are not situated underneath the bus bar and thus are notobscured from view by the bus bar. Note also, that embodiments describedin relation to, e.g., FIGS. 5A, 5B and 7 describe spacers that do notcover any portion of the EC device on a glass lite, either the bus barsor scribe lines. The inventors have appreciated that, when fabricatingan EC window IGU, the spacer can be configured to obscure the bus barsand any isolation scribes in the assembled IGU. These embodiments andvarious related advantages are described in more detail below. Oneembodiment is any EC device described herein, incorporated into an IGU,where the spacer is configured to obscure the bus bars and any scribelines from the viewable area of the EC device. In certain embodiments,the peripheral edge of the EC device is sealed by the primary seal. Inthese embodiments, if a BPE is present, the BPE may also be sealed bythe primary seal.

Conventionally, physical overlap of the metal spacer with the bus barsis avoided so as to avoid electrical shorting between the bus bar andthe metal spacer. That is, typically there is an adhesive between thespacer and the bus bar, but because the IGU formation requires that thecomponents be pressed together, there is a chance of electrical shortingbetween the spacer and the bus bars. Thus, the spacer and bus bars areconfigured so as not to overlap. This offset arrangement reduces theviewable area of the EC window. This defeats the desirable objective ofmaximizing viewable area of an EC window. One way to overcome this issueis to use an insulating spacer, such as a polymeric (foam or non-foamedplastic) spacer or to coat a metal spacer, at least the surface thatwould otherwise come into contact with the bus bar, with an electricallyinsulating material so that the coating is an intervening insulatorbetween the bus bar and the spacer. Such coated spacers are described inU.S. patent application Ser. No. 13/312,057, filed Dec. 6, 2011, titled“Spacers for Insulated Glass Units” which is herein incorporated byreference. Spacers described in application Ser. No. 13/312,057 arecontemplated as suitable for embodiments described herein, therefore oneembodiment is any embodiment described herein that describes a spacer,where the spacer is a spacer described in the Ser. No. 13/312,057application.

Thus, by using appropriate insulative protections, a spacer can bepositioned over a bus bar in order to avoid electrical shorting and alsosave value EC device real estate by obscuring bus bars from the viewablearea of the EC window. The spacer can be positioned to obscure scribelines as well; this is illustrated in FIG. 10. FIG. 10 depicts an IGUhaving an EC device in a low transmissivity (tinted) state where thespacer is not positioned over scribe lines; see the IGU on the left ofFIG. 10. This is compared to an IGU where the spacer is positioned toobscure the scribe lines; see the IGU on the right of FIG. 10. It isapparent that the visible scribe lines in a darkened window aredistracting to the user because of the high contrast between them andthe dark background of the tinted window. The obscured scribe lines arenot visually distracting because they are obscured from view. Oneembodiment is an IGU including at least one EC lite having one or morescribe lines, where all scribe lines are obscured by a spacer of theIGU. In one embodiment the spacer is made of a polymeric material, e.g.,a foam or non-foam material. In one embodiment, the spacer is a metalspacer. In another embodiment the metal spacer includes an insulativecoating at least on a side proximate a bus bar. There are otheradvantages to this configuration besides obscuring scribe lines; theseare discussed in more detail below.

In this context, various embodiments are directed to IGU configurations,where the IGU contains at least one EC device on a lite, andspecifically to the relative orientations and spacial relationshipsbetween the glass panes of an IGU, the spacer, the EC device, any scribelines in the device, bus bars, the primary seal and the secondary seal.The described IGU configurations maximize the viewable area of the ECwindow, while obscuring bus bars and any scribe lines in the EC devicethat would otherwise contrast highly against the tinted EC lite. Also,these embodiments protect the edge of the EC device from the ambientwithin the primary seal of the IGU. These embodiments are described inmore detail below, in relation to FIG. 11.

Conventional IGU's containing an EC device on a transparent substrateare configured in one of two ways with respect to the EC device. In thefirst configuration, the EC device covers the entire area of thesubstrate and the spacer of the IGU rests on the EC device. Thisconfiguration potentially exposes the edges of the EC device to theambient, because the EC device spans the primary seal and the secondaryseal. If additional measures are not taken to protect the outerperimeter of the EC device from moisture and the ambient, e.g. allowinga portion of the secondary sealant or an adjacent laminating adhesive tocover the edge of the EC device, the EC device can degrade over time.Specifically, this configuration allows for a path through the devicelayers for water to enter the otherwise hermetically sealed IGU innerspace and compromise the viewable area of the device. In the secondconfiguration, the device is configured so that its area resides withinthe inner perimeter of the primary seal, i.e. the spacer and theadhesive used to seal the spacer to the glass. That is, the EC device isdoes not run under the spacer, but lies inside the inner perimeter ofthe spacer. In other words, moisture would have to traverse thesecondary seal and the entire primary seal before it could reach the ECdevice within the volume of the IGU. This configuration, although moreprotective of the EC device than the first configuration, sacrificesvaluable EC device footprint in the viewable area of the EC window. Onereason both of these configurations arise (besides the pathway for waterin the first configuration which is avoided in the second configuration)is the bus bar. It is desirable for a number of reasons to use a metalspacer in an IGU. As described above, conventional metal spacers mayshort on the bus bar and thus the bus bars are positioned on either sideof the primary seal, i.e., in the secondary seal area, or within thevolume of the IGU.

In the embodiments described below, the bus bar and any scribe lines areobscured by the primary seal, e.g., they are positioned between thespacer and the glass lite so as not to be viewable to the end user ofthe EC window. The edge of the EC device is protected by the primaryseal directly, the bus bars and scribe lines are not visible to the enduser, and the viewable area of the EC device is maximized. In otherembodiments, the edge delete is performed and then the EC device issealed within a laminate seal, that is, the bonding adhesive of alaminate of the EC substrate with another pane protects the EC device,including the edge portion where the edge delete leaves an exposed edge.One embodiment is a method of processing an EC device including: 1)removing the EC device from a peripheral region of a substrate byelectromagnetic radiation as described herein; and 2) sealing theperipheral edge of the EC device with the primary seal of an IGU orwithin a laminate seal. The dimensions of the peripheral region (edgedelete) are described herein. In one embodiment, the EC device has noscribe lines, only the edge delete and a BPE. In another embodiment, theEC device has only one scribe line, e.g. the scribe line 920 depicted inFIG. 9A.

In certain embodiments, the IGU may be fitted with a capillary breathingtube, e.g. when the IGU is to be deployed at high altitudes and thuspressure changes may necessitate pressure equalizing capability for theIGU. When such capillaries are used, measures are taken to make sure theexchange of gases doesn't allow moisture to enter the IGU, i.e., adrying agent or mechanism is used to dry gases entering the IGU via thecapillary.

FIG. 11 is a partial cross section of an IGU, 1100, specifically aportion of IGU 1100 near to and including the edge of the IGU. Insulatedglass unit 1100 contains two glass substrates (lites) substantiallyparallel to each other (see lower portion of FIG. 2B and associateddescription for general aspects of IGU fabrication). In this example,the lower lite has an EC device, 1110, often referred to as an ECcoating. Typically the EC coating is on the order of less than onemicron thick to a few microns thick, so this figure is not to scale,i.e. the coating's cross section would not be discernible on this scale(also there may be scribe lines, e.g., proximate the bus bar, but theyare not shown). Between the glass lites is a spacer, 1120, which in thisexample is a metal spacer. Between spacer 1120 and the glass lites is aprimary sealant, 1130, for example PIB or other suitable adhesivesealant. This construction is referred to as the primary seal for theIGU; it serves to hermetically seal the interior space, 1150, of the IGUfrom the ambient, and typically the interior space is charged with aninert gas such as argon. Around the perimeter of the primary seal andbetween the lites is a sealant, 1160, which forms the secondary seal ofthe IGU. On EC coating 1110, between spacer 1120 and the lower lite is abus bar, 1170. Bus bar 1170 could also be on a BPE. The bus bar may bebetween about 1 mm and about 5 mm wide, typically about 3 mm wide. Inthis example, spacer 1120 is coated with an insulating material at leaston the side proximate bus bar 1170 so as to avoid inadvertent electricalshorting between the metal spacer and the bus bar. In one embodiment,bus bar 1170 overlaps the edge of the EC device along substantially all,or all, of the length of the EC device. That is, the bus bar residespartially on the device and/or BPE area (penetrating type ornon-penetrating type) while the other portion of the bus bar, along thelength, resides off the device and/or BPE. While not wishing to be boundto theory, it is believed that this configuration may help preventcoloring under the spacer during operation by effectively shorting thedevice in that area. Spacer 1120 could alternatively be a polymericspacer or an insulating material could be applied to the bus bar so thata metal spacer would not short on the bus bar. Also, a metal spacer witha channel to accommodate the bus bar would be suitable.

The dimensions, C, D, E, F and G define a number of configurationalaspects of embodiments of an IGU for maximizing viewable area while atthe same time protecting the edge of the EC device from the ambient inthe primary seal. One such embodiment is an IGU having at least one ofthe dimensions C, D, E, F and G as described below. In one embodiment,the IGU has a configuration that includes all of the dimensions C, D, E,F and G as described below.

The dimension, C, defines the distance between the interior surfaces ofthe glass lites. Dimension C is commonly measured because, e.g., theglass lites may be of different thickness, so the dimension C would bethe same even if the lites were of different thickness. Dimension C isbetween about 6 mm and about 30 mm, between about 10 mm and about 20 mm,or between about 12 mm and about 13 mm. Dimension C also is a measure ofthe height of the primary seal and secondary seal. The length of theprimary seal and secondary seals will depend on the size of the IGU, asthese seals each span a perimeter inside the perimeter of the glasslites of the IGU.

The width of the primary seal approximates, within +2 mm, the width, D,of spacer 1120, with some variation due to sealant 1130 squeezing outbetween the spacer and the glass during IGU fabrication (the negativevariation is due to some sealant not expanding to the width of thespacer). In one embodiment, the width of the spacer is between about 5mm and about 15 mm. In another embodiment, the width of the spacer isbetween about 5 mm and about 10 mm, in another embodiment between about7 mm and 8 mm.

The distance, E, defines the width of the secondary seal. In oneembodiment, the secondary seal is between about 2 mm and about 15 mmwide, in another embodiment between about 3 mm and about 10 mm wide, andin yet another embodiment between about 4 mm and about 8 mm wide. Thewidth of the secondary seal may be set independently of the otherdimensions described in relation to FIG. 11, or, e.g., may be set as anartifact of the choice for dimensions D, F and G. Dimensions F and G aredescribed below.

The distance, F, is the backset, which is the distance between the inneredge of the spacer and the inner edge of a bus bar or a scribe. Thebackset is a measure of how far “back” a bus bar or scribe is positionedfrom the inner edge of the spacer, so as to obscure the bus bar and/orscribe from the viewable area of the EC coating. In one embodiment, thebackset is between about 1 mm and about 5 mm, in another embodiment,between about 2 mm and about 3 mm, in yet another embodiment about 2 mm.The backset may vary from one side of the IGU to another, as in thedescribed embodiments, the spacer is configured to obscure thesefeatures, and these features need not be symmetrically dimensioned withrespect to the spacer, the spacer need only obscure them. In other wordsthe backset for a given feature, a scribe line or a bus bar may bedifferent on one side of the IGU as compared to another side of the IGU.FIG. 11 shows that the edge of EC device 1110 is protected by theprimary seal. The backset allows any bus bar or scribe line to beobscured and ensures the edge of the EC device is protected by theprimary seal.

In one embodiment, the primary seal is a two-part seal. For example theportion of the primary seal that protects the edge of the EC device is apolymeric adhesive seal as depicted, while the outer portion, nearer theouter side of the spacer, where the spacer is over the edge delete area,the seal is a diffusion bonding type seal, where the metal spacer andglass are diffusion bonded on that portion of the spacer.

The distance, G, is a measure of the edge delete as described above.This is the width of the perimeter portion of the EC device removed toexpose the glass and/or the diffusion barrier. As described above, inone embodiment, the perimeter portion is between about 1 mm and about 20mm wide, in another embodiment between about 5 mm and about 15 mm wide,and in yet another embodiment between about 8 mm and about 10 mm wide.In one embodiment the glass is exposed, that is, the EC device and anydiffusion barrier are removed in the edge delete. In one embodiment, theedge delete is performed so as to also remove between about 0.5micrometers (μm) and about 3 μm of the glass substrate, e.g. to ensurecomplete removal of the EC device and diffusion barrier (accounting forvariation in thickness and planarity of the substrate). In oneembodiment, the edge delete is performed so as to also remove betweenabout 1 μm and about 2 μm of the glass substrate. In another embodiment,the edge delete is performed so as to also remove about 1.5 μm of theglass substrate.

One embodiment is an IGU where C is between about 12 mm and about 13 mm,D is between about 7 mm and about 8 mm, E is between about 4 mm andabout 8 mm, F is between about 2 mm and about 3 mm, and G is betweenabout 8 mm and about 10 mm. In one embodiment, the IGU has two glasspanes that are each, independently, between about 3 mm and about 6 mmthick. In one embodiment, the thickness of each of the glass panes isthe same. In another embodiment, the thickness of the glass panes doesnot differ by more than 1 mm.

Although the foregoing invention has been described in some detail tofacilitate understanding, the described embodiments are to be consideredillustrative and not limiting. It will be apparent to one of ordinaryskill in the art that certain changes and modifications can be practicedwithin the scope of the appended claims.

We claim:
 1. A method of fabricating an electrochromic windowcomprising: i. coating a rectangular transparent substrate with anelectrochromic device; ii. edge deleting a perimeter portion, betweenabout 5 mm and about 15 mm wide, of the electrochromic device about theperimeter of the rectangular transparent substrate; iii. removing aportion of the electrochromic device along one edge to expose a lowertransparent conducting oxide layer to form a bus bar pad expose area;and iv. sealing the peripheral edge of the electrochromic device withinthe primary seal of an insulated glass unit.
 2. The method of claim 1,further comprising applying a first bus bar to the bus bar pad exposearea.
 3. The method of claim 2, wherein the bus bar pad expose area issubstantially rectangular, the length approximating said one edge of theelectrochromic device and where the width is between about 5 mm andabout 10 mm.
 4. The method of claim 3, wherein the first bus bar and theelectrochromic device edge proximate the first bus bar are separated bya gap between about 1 mm and about 3 mm.
 5. The method of claim 4,wherein the first bus bar is a non-penetrating bus bar.
 6. The method ofclaim 4, wherein a second bus bar is applied to a top transparentconducting oxide layer of the electrochromic device and the rectangulartransparent substrate is incorporated into an insulated glass unit. 7.The method of claim 6, wherein the first and second bus bars areobscured from the viewable area of the insulated glass unit by a spacerof the insulated glass unit.
 8. The method of claim 1, wherein the busbar pad expose area is sealed within the primary seal of the insulatedglass unit.
 9. The method of claim 1, wherein the edge deletion isperformed before the forming the bus bar pad expose area.
 10. The methodof claim 1, further comprising applying a first bus bar to the bus barpad expose area, where the first bus bar overlaps the edge of the busbar pad expose area and touches the rectangular transparent substrate.11. The method of claim 10, wherein a gap between the first bus bar andthe edge of the electrochromic device proximate the first bust bar isbetween about 1 mm and about 3 mm.
 12. The method of claim 1, whereiniii comprises using laser ablation to selectively remove materials abovethe lower transparent conducting oxide layer based on absorptioncharacteristics of the materials above the lower transparent conductingoxide layer.
 13. The method of claim 1, wherein ii and/or iii compriseusing laser ablation from either the electrochromic device side or theopposite side of the rectangular transparent substrate.
 14. The methodof claim 13, wherein the energy density of a laser beam used for laserablation is between about 0.5 J/cm² and about 4 J/cm².
 15. The method ofclaim 7, wherein the spacer is an electrically insulated spacer.
 16. Themethod of claim 15, wherein the electrically insulated spacer is a metalspacer coated with an electrically insulating material.
 17. The methodof claim 15, wherein the electrically insulated spacer is a polymericspacer.
 18. The method of claim 17, wherein the polymeric spacer is afoam spacer.
 19. The method of claim 7, wherein the spacer includes adesiccant inside it.
 20. The method of claim 7, wherein the distancebetween the edge of the rectangular transparent substrate and the outeredge of the spacer is between about 2 mm and about 15 mm.